He is the 21st century David Fairclough, the Etihad Stadium Javier Hernandez. Besides being the scourge of Spurs, Edin Dzeko is Manchester City's brilliant Plan B. He is not so much the super-sub as the superlative substitute, the replacement who wreaks havoc. Except, of course, when he actually begins a game.

The latest chapter of an increasingly familiar story condemned Tottenham to a 2-1 defeat and cemented his paradoxical position. His importance is almost unrivalled, yet he is better coming off the bench. Dzeko has a statistical significance very few starters can rival.

Of his six league goals, five have come as a replacement. They have earned nine points, the combined total of two Premier League clubs between them. And that is before his injury-time leveller against QPR, preceding Sergio Aguero's title-winning strike in May, is invoked.

"If there is a comparable situation to this one, it is Chicharito's," said Andre Villas-Boas, a defeated manager turned analyst of impact players. "A player so strong of character like Dzeko to come on when his team needs him deserves great credit."

But if Hernandez is the smiling substitute, Dzeko is an altogether grumpier one. "He is not happy," said Roberto Mancini. "A player who is happy on the bench does not exist." Indeed, the match-winner himself suggested as much. In football parlance, he is letting his feet do the talking. "The goals are my message [to Mancini]," he said.

The latest was created with class and taken terrifically. David Silva, with the deftness City have been missing, chipped a pass over the Tottenham defence. Dzeko bounded on to it and hooked his shot past Brad Friedel. After a quartet of goals against Spurs last season came a single crucial strike this time around. "An individual moment of brilliance from Dzeko which I think is recurrent," added Villas-Boas. "He continues to be on the bench and come on to destroy opposition."

After losing leads to Chelsea and now City, the Tottenham manager has become a student of comebacks. His City counterpart has a PhD in them. "I saw the same spirit from the players that I saw last year," Mancini said. Despite City's struggles, it has been evident for much of the current campaign: this was the fourth time they have transformed defeat into victory in the Premier League.

Their manager pursues an idiosyncratic path to the points. There is the easy option and there is the Mancini way. The interfering Italian tends to court controversy in his choices but his stubbornness has its benefits. Behind to Steven Caulker's goal, Mancini's response was not merely to switch to his much-maligned 3-5-2 formation, but to introduce Maicon, to loud cheers from the Tottenham fans who remembered his savaging at the hands of Gareth Bale two years ago. It was a decision that had the potential to backfire horribly.

But, while the previously quiet Welshman was more prominent thereafter, it proved a masterstroke. As Villas-Boas accepted, Mancini's tactical tinkering altered the game. "Man City made some changes and put three at the back to go all-out attack," he said, before revealing Tottenham had considered a like-for-like switch. "During this week, we worked on three at the back too because we knew it could serve us at certain moments in the game," he added. "We didn't use it today because with four [at the back] we looked stable."

The impact could be measured in terms of impetus for City. It enabled them to get Silva into a central area. Already influential, he began to fashion chance after chance. Following his hamstring injury, City have their creator in chief back and, after a stop-start season, their most clinical striker is starting to look at his sharpest, too.

With two goals in as many games, Aguero is providing reminders of his magnificent debut campaign in England. The Argentine equalised with a devastating display of his speed and skill, to meet Yaya Toure's pass, skip past Jan Vertonghen and beat Friedel.

Then Aguero, Silva and Dzeko all came close to a winner before the Bosnian delivered it. "He has got some heavy goals," said City coach David Platt, finding a different way to describe the striker's decisive interventions.

Villas-Boas, no stranger to an unusual turn of phrase, coined another when considering the effect of Mancini's change of shape. "It gave them more attacking volume," he said. City are not the noisy neighbours for nothing.

MAN OF THE MATCH: David Silva – Substance and steel in one diminutive, deadly package. Every statistic suggests City are a better team with the Spaniard in. The naked eye gives the same impression, too. While the slight Silva can look a frail figure, he surprised the City management by still being on the field, 88 minutes in to his comeback from a hamstring injury, to set up Dzeko's winner.

MANCHESTER CITY VERDICT: If Dzeko's role as the rescuer was one recycled plot line, there was another as, once again, they conceded from a set-piece. Matija Nastasic lost Caulker for the goal and the young Serb is particularly culpable for their dead-ball difficulties. He was the man sacrificed in the switch to three at the back while another deemed surplus to requirements, Mario Balotelli, did not even make the bench. Joe Hart, too, should have done better with the Spurs goal and after having two penalty appeals rejected, it was shaping up to be another frustrating outing for City until they rallied. Samir Nasri missed the game through illness but he, Joleon Lescott, Jack Rodwell and James Milner could all be in contention for the visit of Aston Villa on Saturday.

TOTTENHAM VERDICT: Like Mancini, Villas-Boas sometimes goes for the controversial choice. Dropping top scorer Jermain Defoe and selecting Emmanuel Adebayor was a case in point but, at his former club, the Togolese showed he offers a real outlet as the lone striker. With Clint Dempsey almost anonymous and Bale enduring one of his quieter days, there were times when it seemed Adebayor was taking on the City defence on his own. Tom Huddlestone, another who had seemed out of favour, supplied the goal and showed some quality. However, Kyle Walker was taken off with a hamstring problem, rendering him a doubt for England's friendly in Sweden. After losing three of their last four league games, Saturday's North London derby assumes huge importance for Spurs.